Help

hey i hope i can ask this here cause it has to do with icons. but im wanting to make some animations and i dont have a screencapture program for my computer that works for Macs. anyways i have a avi of the movie parts i want to make into a gif icon. but i dont have a program so i was wondering if anyone knew of a program that works on macs that can make the avi file with screencaps frame by frame.

i hope that makes sense. anyways thanks for anyone who can help me.